Electric printing-machine



G. W. JOHNSON.

ELECTRlC PRINTING MACHINE.

APPLICATION FILED JAN.2B. 1919.

Patented Aug. 31,1920.

WITNESSES I N VEN TOR. Geage 1 15/5517:) 7

A TTORNE Y.

UNITED STATES GEORGE W. JOHNSON, 0F LATROBE, PENNSYLVANIA.

ELECTRIC PRINTING-MACHINE.

Specification of Letters Patent.

Patented Aug. 31, 1920.

Application filed January 28, 1919. Serial No. 273,529

To all whom it may (Jon/urn c it known that I, (inonon W. JOHNSON, a citizen of the United States, residing at Latrobe, in the county of lVestmoreland and State of Pennsylvania, have invented certain new and useful Improvements in Electric Printing-Machines, of which the following is a specification.

This invention relates to photography,

and more especially to printing, and the obmay be serviceable tor lighting the dark room.

A detail of the invention consists in the automatic means for closing the switch to the strong light when the door of the machine is closed.

Details are set forth below. and attention is drawn to the drawings, wherein" Figure 1 is a perspective view of this ma chine open.

Fig. 2 is an enlarged vertical section of the machine With the door closed.

Fig. 3 is a diagram showing the wiring.

The numeral 1 designates a box-like casing having at its top a cover 2 hinged at its rear at 3 and adapted when closed down to be fastened in place by means of a hook and eye connection, 4, 5 at each side. The front upper corner of the box is beveled of? as at 6 and the base 7 projects forward and a tiords a table 8. The beveled panel 6 is provided with-an opening 16 surrounded on its in terior by a flange 17 on which lies a pane of glass 18. Connected with the panel 6 at one end of the opening by any suitable nieans as by hinges (notlshown). is a two part door 19 whereof the parts are hinged to each other and lined on their inner faces with fabric so as to closely overlie the sensitive paper and film when the same are laid upon the glass. At the free edge the door carries a tongue 11 adapted to fall into a recess or notch 12 in the panel 6. and the tip of the tongue. is connected with the body of the casing by hook and eye elements 14. 15 as shown. The position of these elements is such that when they are engaged the tongue is drawn tight down into the recess or notch 12 and the door tight into the opening 16. upon the glass, with the paper and filni intervening.

(arried by the panel 6 at an appropriate point, and herein shown as above the open 111g i6, is a weak light and preferably an incandescent bulb having a red or ruby globe as indicated at H. Mounted upon a suitable support 20 within the box-like cas ing 1, is a strong light, prefcrabl a white incandescent bulb indicated at W. A twd \vire cable 21 leads into the casing, either through the opening beneath its cover or any appropriate point, and the wircs are then diverted and one of them led through a knife switch -22 as shown the Wiring being perhaps best illustrated in Fig. 3. To the free end of the blade of the switch connected a rod 23 having a head 21 normally raised by a spring 25, and above this head is a plunger 26 whose head 27 in turn rises into the notch and recess 12. When now the tongue is brought over into said recess it bears on the head 27 and deprcsscs the plunger. and the plunger in turn bears on the head 24 and depresses lhc rod. This in turn depresses the free end of thc switch blade. so that a circuit is closed to the large white lamp V. and the sainc is llllllllllltltll'l at a time when the sensitive paper and lilm has been tightly clamped down upon-the glass 18 within the periphery of the opening 16. The obvious purpose of having the door 19 in twoparts is to permit the operator to unlatch the outer leaf or part and swing it back, while holding the inner leaf or part and the film and paper. and turn up the paper to ascertain to what extent the printing has been carried. This is well known to photographers. Obviously he may restore the parts to their position, and pressure on the tongue before it can be booked in )lace cuts on the current and the bulb V is immediately lighted. So long as the current flows from the source of electricity, the ruby globe R is lighted and afl'ords light to the whole interior of the dark room within which this machine is located. and it also gives direct light upon the film and the picture being printed. when the door is turned back wholly or in part. Unless the operator shall deliberatelypress upon the head 27 of the plunger 26. it ls impossible to close the switch 22, and there fore the bull) \V will not be illuminated until the door 19 is closed. This of course will not occur until the Iiln'i and paper have been placed in position and the cover losed and hooked. It is possible that the raid 31 may have a plug at its rerun. cud (not shown) to lie conneclcd lo any ordinary socket in the house sysu-nn and when this dericc is not in use the cable and its plug may he placed within the casing and the cover closed and hooked.

The foregoing description and the drawings have reference to what may he cow sidered the preferred or approved form of my inrcntion. lt is to he nndcrstoml lhai l may make such changes in construction and arrangement and ci'inillinalion of parts. nialkliillm dimensions, et vctcra, as may prove wpwli nl and fall \\il1i|i iii. Mllk' ol' llll llllnlfll l'tl k'lillll).

lliuine thus fully dm -rilwd my inn-n lion. what I claim as 11c and \lcsirv lo \n-uro ll licllcis Patent is" in a device of the character described. the combination of a casin; including a circuit therein having a lamp and a knife switch, a rod connected to said knife switch and having a head on its outer end, a coiled spring surrounding said rod and engaging said head for forcing the same in one dime lion lo hold the switch normally open, an aliulincnt, means on said casing for said spring. said head adapted lo con'ipress said coil s ring against said ahutment, said casine having a print receiving portion proridcd with a scvtionnl door, said easing havin; a recess contiguous to the receiving por- Lioin a plunger extending into said recess and having, its inner and contacting with the head of said. red, a tongue extendin from one section of the door and adeptea in he received within the recess asthe door is closed to strike said plunger and cause llic same to depress said rod to close the snilili. although when one section of the llnUl' is opened for the usual purposes the t neu will lH r inorml'irom the plunger In 'IHI Iill1Hl)l'lll;1lHllfltlilltlptflltllGSWillfil, fls and for the purposes set forth.

In testimony whereof I afiiy my signature in lil\"-(lllt of two witncsses.

GEORGE W'. JOHNSON.

Witnesses GUs'r. ANToN, E. 0. SMITH. 

